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Published on 1 Comment on A Little Alcohol Daily May Be Beneficial

Interesting new research found health benefits to the brain from daily low intake of alcohol (equivalent to about 2 1/2 drinks per day). The University of Rochester (in New York) researchers found that while low daily (chronic) levels of alcohol were beneficial to the brain's glymphatic system, higher daily levels or binge drinking was not. And the low daily levels of alcohol intake was also better for the glymphatic system than no alcohol at all (the control group). In 2015 this same research team described the glymphatic system as not just the brain’s “waste-clearance system,” but as potentially helping fuel the brain by transporting glucose, lipids, amino acids, and neurotransmitters.

I'm sure this study will be greeted by many as great news, but remember it was done with MICE, and not humans, so one should be cautious in generalizing the results. But the researchers think that it does apply to humans, and may explain why some studies find some health benefits to low levels of daily alcohol intake, even better than no alcohol, and many negative effects to higher levels of alcohol intake - thus the J-shaped curve of effects seen in studies. [NOTE: Studies also find that alcohol consumption can cause cancer, and this is dose related. Studies find the Mediterranean diet (which includes low to moderate levels of alcohol) beneficial for brain health.]

By the way - no, the mice didn't receive wine as the press release from the Univ. of Rochester says. The mice actually received "intraperitoneal injections of low, intermediate, and high doses of ethanol" or just plain saline (the control group). From Science Daily:

In wine, there's health: Low levels of alcohol good for the brain

While a couple of glasses of wine can help clear the mind after a busy day, new research shows that it may actually help clean the mind as well. The new study, which appears in the journal Scientific Reports, shows that low levels of alcohol consumption tamp down inflammation and helps the brain clear away toxins, including those associated with Alzheimer's disease.

"Prolonged intake of excessive amounts of ethanol is known to have adverse effects on the central nervous system," said Maiken Nedergaard, M.D., D.M.Sc., co-director of the Center for Translational Neuromedicine at the University of Rochester Medical Center (URMC) and lead author of the study. "However, in this study we have shown for the first time that low doses of alcohol are potentially beneficial to brain health, namely it improves the brain's ability to remove waste." The finding adds to a growing body of research that point to the health benefits of low doses of alcohol. While excessive consumption of alcohol is a well-documented health hazard, many studies have linked lower levels of drinking with a reduced risk of cardiovascular diseases as well as a number of cancers.

Nedergaard's research focuses on the glymphatic system, the brain's unique cleaning process that was first described by Nedergaard and her colleagues in 2012. They showed how cerebral spinal fluid (CSF) is pumped into brain tissue and flushes away waste, including the proteins beta amyloid and tau that are associated with Alzheimer's disease and other forms of dementia. Subsequent research has shown that the glymphatic system is more active while we sleep, can be damaged by stroke and trauma, and improves with exercise.

The new study, which was conducted in mice, looked at the impact of both acute and chronic alcohol exposure. When they studied the brains of animals exposed to high levels of alcohol over a long period of time, the researchers observed high levels of a molecular marker for inflammation, particularly in cells called astrocytes which are key regulators of the glymphatic system. They also noted impairment of the animal's cognitive abilities and motor skills.

Animals that were exposed to low levels of alcohol consumption, analogous to approximately 2 ½ drinks per day, actually showed less inflammation in the brain and their glymphatic system was more efficient in moving CSF through the brain and removing waste, compared to control mice who were not exposed to alcohol. The low dose animals' performance in the cognitive and motor tests was identical to the controls.

"The data on the effects of alcohol on the glymphatic system seemingly matches the J-shaped model relating to the dose effects of alcohol on general health and mortality, whereby low doses of alcohol are beneficial, while excessive consumption is detrimental to overall health" said Nedergaard. "Studies have shown that low-to-moderate alcohol intake is associated with a lesser risk of dementia, while heavy drinking for many years confers an increased risk of cognitive decline. This study may help explain why this occurs. Specifically, low doses of alcohol appear to improve overall brain health." [Original study. Especially interesting is the Introduction & Discussion sections.]

Published on Leave a comment on Moderate Drinking Associated With Harm to the Brain

Uh-oh... looks like any benefits of moderate alcohol consumption may not extend to the brain, at least in men. A  recent study found that moderate alcohol consumption over the course of a 30 years was associated with increased odds of hippocampal atrophy (brain damage in the hippocampus of the brain) - when compared to abstainers. Hippocampal atrophy causes memory problems and affects spatial navigation, and is also an early characteristic of Alzheimer's disease and other dementias. This result occurred in a dose dependent fashion - meaning the more that was drunk regularly, the more the atrophy in that area of the brain.

The heavier drinkers (when compared to abstainers) also had a faster decline in verbal skills ('verbal fluency") and changes in the white matter of the brain (specifically "corpus callosum microstructure"). There was no protective effect of light drinking when compared to abstainers (the 2 groups had similar results). **However, the researchers also reported: "The hippocampal atrophy associations we found in the total sample were replicated in men alone but not in women." Note: there were few women in the study (only 103 out of 527 studied) and even fewer were "heavy" drinkers (14 women), but one wonders - why not? Why didn't women drinkers have these brain changes?**

So how much did the moderate drinkers drink? They really didn't drink that much, but there were different groups: the abstainers (less than 1 unit of alcohol a week), “light” drinking was between 1 and <7 units, “moderate” drinking as 7 to <14 units a week for women and 7 to <21 units for men, and the heavier drinkers - those that drank more units per week, for an average of 30 units a week. What is a "unit" of alcohol? A medium glass of wine has about two units of alcohol, and so does a pint of  ordinary strength beer or lager. Thus the male moderate drinkers drank about a medium glass of wine or a beer each night, and maybe a little extra on the weekends. (In other words, not that much.) And the heaviest drinkers had a little more than two medium glasses of wine or two beers every night of the week, plus a little more on weekends.

What do the results mean?  The researchers said that  they don't have any evidence linking the brain changes they saw on the MRI brain scans to any negative general cognitive effects, but they did lose more "language fluency" with time. (They gave the people various tests.) The abstainer group (37 people) was very small - perhaps other lifestyle factors (e.g., nutrition) may be playing a part in the results. Also, if people  under-reported actual alcohol consumption - then it would throw off the results. While studies show that drinking can increase cancer risk, other studies have found that moderate drinkers seem to live longer than abstainers. From Medical Xpress:

Even moderate drinking linked to a decline in brain health, finds study

Alcohol consumption, even at moderate levels, is associated with increased risk of adverse brain outcomes and steeper decline in cognitive (mental) skills, finds a study published by The BMJ today. Heavy drinking is known to be associated with poor brain health, but few studies have examined the effects of moderate drinking on the brain—and results are inconsistent. So a team of researchers based at the University of Oxford and University College London set out to investigate whether moderate alcohol consumption has a beneficial or harmful association—or no association at all—with brain structure and function.

They used data on weekly alcohol intake and cognitive performance measured repeatedly over 30 years (1985-2015) for 550 healthy men and women who were taking part in the Whitehall II study. This study is evaluating the impact of social and economic factors on the long term health of around 10,000 British adults. Participants had an average age of 43 at the start of the study and none were alcohol dependent. Brain function tests were carried out at regular intervals and at the end of the study (2012-15), participants underwent an MRI brain scan.... After adjusting for these confounders, the researchers found that higher alcohol consumption over the 30 year study period was associated with increased risk of hippocampal atrophy - a form of brain damage that affects memory and spatial navigation.

While those consuming over 30 units a week were at the highest risk compared with abstainers, even those drinking moderately (14-21 units per week) were three times more likely to have hippocampal atrophy compared with abstainers. There was no protective effect of light drinking (up to 7 units per week) over abstinence.

Higher consumption was also associated with poorer white matter integrity (critical for efficient cognitive functioning) and faster decline in language fluency (how many words beginning with a specific letter can be generated in one minute). But no association was found with semantic fluency (how many words in a specific category can be named in one minute) or word recall. The authors point out that this is an observational study, so no firm conclusions can be drawn about cause and effect, and say some limitations could have introduced bias. [Original study.]

Published on Leave a comment on Strong Evidence That Alcohol Causes Seven Cancers

A medical article in the journal Addiction states that there is strong evidence that alcohol causes 7 cancers, that there is evidence that it probably causes more, the effects are dose related, and if one also smokes the risks are greatly increased. The 7 cancers are: oropharynx (mouth and pharynx), larynx, esophagus, liver, colon, rectum, and female breast.

An earlier post reported on conflicting results from some studies (e.g. that low to moderate alcohol consumption is beneficial), as well as the finding that effects are dose-related (the more alcohol a person drinks, the higher the risk of cancer). NOTE: One standard drink contains 14 grams of alcohol, and is equivalent to one ordinary beer, a glass of wine (5 oz), or a nip of spirits (1.5 oz or 44 ml). The article excerpts below state that the strongest effects are from consuming 50 grams or more of alcohol per day (compared to those who don't drink at all).

From Medscape: No Confusion: Alcohol Causes Seven Cancers

There is "strong evidence" that alcohol causes seven cancers, and other evidence indicates that it "probably" causes more, according to a new literature review published online July 21 in Addiction. Epidemiologic evidence supports a causal association of alcohol consumption and cancers of the oropharynx, larynx, esophagus, liver, colon, rectum, and female breast, says Jennie Connor, MB, ChB, MPH, from the Department of Preventive and Social Medicine, University of Otago, in Dunegin, New Zealand.

In short, alcohol causes cancer. This is not news, says Dr Connor. The International Agency for Research on Cancer (IARC) and other agencies have long identified alcohol consumption as being causally associated with these seven cancers. So why did Dr Connor, who is an epidemiologist and physician, write a new review? Because she wants to "clarify the strength of the evidence" in an "accessible way." 

The newly published review "reinforces the need for the public to be made aware of the causal link between alcohol and cancer," said Colin Shevills, from the Alcohol Health Alliance UK, in a press statement....The lack of clarity about alcohol causing cancer, Dr Connor believes, is related to alcohol industry propaganda as well as the fact that the "epidemiological basis for causal inference is an iterative process that is never completed fully."

Dr Connor writes that the strength of the association of alcohol as a cause of cancer varies by bodily site. The evidence is "particularly strong" for cancer of the mouth, pharynx, and esophagus (relative risk, ~4-7 for ≥50 g/day of alcohol compared with no drinking) but is less so for colorectal cancer and liver and breast cancer (relative risk, ~1.5 for ≥50 g/day). "For cancers of the mouth, pharynx, larynx and oesophagus there is a well-recognized interaction of alcohol with smoking, resulting a multiplicative effect on risk," adds Dr Connor.

Other cancers are also likely caused by alcohol. Dr Connor writes that there is "accumulating research" supporting a causal contribution of alcohol to cancer of the pancreas, prostate, and skin (melanoma). One British expert had an opinion about alcohol's carcinogenicity. In a statement about the new review, Prof Dorothy Bennett, director of the Molecular and Clinical Sciences Research Institute at St. George's, University of London, said: "Alcohol enters cells very easily, and is then converted into acetaldehyde, which can damage DNA and is a known carcinogen."

In the new review, Dr Connor describes various hallmarks of causality that have been found in epidemiologic studies of alcohol and these seven cancers, such as a dose-response relationship and the fact that the risk for some of these cancers (esophageal, head and neck, and liver) attenuates when drinking ceases. Current estimates suggest that alcohol-attributable cancers at the seven cancer sites make up 5.8% of all cancer deaths worldwide, she states. The alcohol industry has a lot at stake, she says, which in turn leads to "misinformation" that "undermines research findings and contradicts evidence-based public health messages."

But there is no safe level of drinking with respect to cancer, says Dr Connor, citing research about low to moderate levels of alcohol, which has been covered by Medscape Medical News. This was also the conclusion of the 2014 World Cancer Report, issued by the World Health Organization's IARC.

Published on Leave a comment on Can A Healthy Lifestyle Prevent Cancer?

Another new study about lifestyle and the risk of cancer. Many earlier studies have established some lifestyle factors that increase cancer risk: smoking, alcohol use, obesity, and physical inactivity. In this study the researchers found that about 20% to 40% of cancer cases and about half of cancer deaths can be potentially prevented through lifestyle modification.

For some cancers the the effect is even larger - for example, approximately 80% to 90% of lung cancer deaths could be avoided if Americans adopted the lifestyle of the low-risk group, mainly by quitting smoking. For other cancers, from 10% to 70% of deaths could be prevented. Bottom line: making some lifestyle changes could change a person's cancer risk.

From Science Daily: Can a healthy lifestyle prevent cancer?

A large proportion of cancer cases and deaths among U.S. individuals who are white might be prevented if people quit smoking, avoided heavy drinking, maintained a BMI between 18.5 and 27.5, and got moderate weekly exercise for at least 150 minutes or vigorous exercise for at least 75 minutes, according to a new study published online by JAMA Oncology. Cancer is a leading cause of death in the United States.

Mingyang Song, M.D., Sc.D., of Massachusetts General Hospital, Harvard Medical School and the Harvard T.H. Chan School of Public Health, Boston, and Edward Giovannucci, M.D., Sc.D., of the Harvard T.H. Chan School of Public Health and Harvard Medical School, Boston, analyzed data from two study groups of white individuals to examine the associations between a "healthy lifestyle pattern" and cancer incidence and death.

A "healthy lifestyle pattern" was defined as never or past smoking; no or moderate drinking of alcohol (one or less drink a day for women, two or less drinks a day for men); BMI of at least 18.5 but lower than 27.5; and weekly aerobic physical activity of at least 150 minutes moderate intensity or 75 minutes vigorous intensity. Individuals who met all four criteria were considered low risk and everyone else was high risk. The study included 89,571 women and 46,399 men; 16,531 women and 11,731 had a healthy lifestyle pattern (low-risk group) and the remaining 73,040 women and 34,608 men were high risk.

The authors suggest about 20 percent to 40 percent of cancer cases and about half of cancer deaths could potentially be prevented through modifications to adopt the healthy lifestyle pattern of the low-risk group.The authors note that including only white individuals in their PAR estimates may not be generalizable to other ethnic groups but the factors they considered have been established as risk factors in diverse ethnic groups too.

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Most people know that heavy drinking of alcohol, smoking marijuana, cigarette smoking, and using methamphetamine during pregnancy should be avoided because they can have negative effects on the developing fetus. However, this study found that each of these also had a distinct negative effect on the placenta, suggesting that "different mechanisms mediate their effects on placental development". From Science Daily:

Effects of alcohol, methamphetamine, and marijuana exposure on the placenta

In the United States, prenatal alcohol exposure (PAE) is the most common preventable cause of developmental delay. Animal studies have shown some of the adverse effects of PAE on placental development, but few studies have examined these effects in humans. This is the first study to examine the effects of prenatal exposure to methamphetamine, marijuana, and cigarette smoking on human placental development.

Researchers collected placentas from 103 Cape Coloured (mixed ancestry) pregnant women recruited at their first antenatal clinic visit in Cape Town, South Africa. Of these, 66 heavy drinkers and 37 non-drinkers were interviewed about their alcohol, cigarette smoking, and drug use at three antenatal visits. A senior pathologist, blinded to exposure status, performed comprehensive pathology examinations on each placenta using a standardized protocol. In multivariable regression models, effects of prenatal exposure were examined on placental size, structure, and presence of infections and meconium.

Results show that alcohol, methamphetamine, and marijuana were associated with distinct patterns of pathology, suggesting that different mechanisms mediate their effects on placental development. Alcohol exposure was related to decreased placental weight and a smaller placenta-to-birth weight ratio. By contrast, methamphetamine was associated with larger placental weight and a larger placenta-to-birth weight ratio. Marijuana was also associated with larger placental weight. In addition, alcohol exposure was associated with an increased risk of placental hemorrhage. Finally, alcohol and cigarette smoking were associated with a decreased risk of intrauterine passing of meconium, a sign of acute fetal stress and/or hypoxia; methamphetamine, with an increased risk. These findings may be important in the long-term teratogenic effects of prenatal alcohol and drug exposure.

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It's interesting how drinking alcohol seems to have a J-curve for health effects. Light drinkers seem to do the best, but heavy drinkers do the worst of all groups (also see earlier posts). This research (published this week in the journal Stroke) shows that drinking more than 2 drinks a day in middle age is a bigger risk factor (double the risk) for a stroke between the ages of 60 to 75 years than high blood pressure, diabetes, or genetics. And once again, looking at the study one can see that nondrinkers had a small increased risk for stroke vs very light drinkers. From Science Daily:

Heavy drinking in middle-age may increase stroke risk more than traditional factors

Drinking more than two alcoholic beverages a day in middle-age raised stroke risks more than traditional factors such as high blood pressure and diabetes. Heavy drinking in mid-life was linked to having a stroke about five years earlier in life irrespective of genetic and early-life factors.

In a study of 11,644 middle-aged Swedish twins who were followed for 43 years, researchers compared the effects of an average of more than two drinks daily ("heavy drinking") to less than half a drink daily ("light drinking").

The study showed that: - Heavy drinkers had about a 34 percent higher risk of stroke compared to light drinkers. - Mid-life heavy drinkers (in their 50s and 60s) were likely to have a stroke five years earlier in life irrespective of genetic and early-life factors. - Heavy drinkers had increased stroke risk in their mid-life compared to well-known risk factors like high blood pressure and diabetes. - At around age 75, blood pressure and diabetes appeared to take over as one of the main influences on having a stroke.

Researchers analyzed results from the Swedish Twin Registry of same-sex twins who answered questionnaires in 1967-70. All twins were under age 60 at the start. By 2010, the registry yielded 43 years of follow-up, including hospital discharge and cause of death data. ... Almost 30 percent of participants had a stroke. They were categorized as light, moderate, heavy or non-drinkers based on the questionnaires. 

Among identical twin pairs, siblings who had a stroke drank more than their siblings who hadn't had a stroke, suggesting that mid-life drinking raises stroke risks regardless of genetics and early lifestyle.

The study is consistent with the American Heart Association's recommended limit of two drinks a day for men and one for women. That's about 8 ounces of wine (two drinks) for a man and 4 ounces (one drink) for a woman. Regular heavy drinking of any kind of alcohol can raise blood pressure and cause heart failure or irregular heartbeats over time with repeated drinking, in addition to stroke and other risks.

Published on

Over the past year I have seen a number of studies looking at alcohol consumption and health effects. Overall it seems that the effects of alcohol are complex and frequently result in a J-curve: abstainers have a higher mortality rate or problems, light or moderate drinkers do the best, and then heavier drinkers have the most problems and higher mortality rates. The following two studies support this. From Science Daily:

Drinking moderate amounts of alcohol is linked to reduced risk of heart failure, large study finds

Evidence already exists for the beneficial effects of drinking moderate amounts of alcohol on the risk of developing a number of heart conditions; however, the role it plays in the risk of developing heart failure has been under-researched with conflicting results. Now, a large study of nearly 15,000 men and women shows that drinking up to seven drinks a week in early to middle age is associated with a 20% lower risk of men developing heart failure in the future when compared to people who did not drink at all, and a more modest 16% reduced risk for women.

They defined a drink as one that contains 14g of alcohol, equivalent to approximately one small (125ml) glass of wine, just over half a pint or a third of a litre of beer, and less than one shot of liquor such as whisky or vodka. The study participants were divided into six categories: abstainers (people who recorded having drunk no alcohol at every visit by the researchers), former drinkers, people who drank up to seven drinks a week, or between 7-14 drinks, 14-21 drinks, or 21 or more drinks a week.

From Science Daily:

If you're over 60, drink up: Alcohol associated with better memory

For people 60 and older who do not have dementia, light alcohol consumption during late life is associated with higher episodic memory -- the ability to recall memories of events -- researchers report.

Moderate alcohol consumption was also linked with a larger volume in the hippocampus, a brain region critical for episodic memory. The relationship between light alcohol consumption and episodic memory goes away if hippocampal volume is factored in, providing new evidence that hippocampal functioning is the critical factor in these improvements.

Findings from animal studies suggest that moderate alcohol consumption may contribute to preserved hippocampal volume by promoting generation of new nerve cells in the hippocampus. In addition, exposing the brain to moderate amounts of alcohol may increase the release of brain chemicals involved with cognitive, or information processing, functions.

Although the potential benefits of light to moderate alcohol consumption to cognitive learning and memory later in life have been consistently reported, extended periods of abusing alcohol, often defined as having five or more alcoholic beverages during a single drinking occasion is known to be harmful to the brain.

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I've been seeing research report after report looking at how our lifestyle determines how we'll age - whether we'll be active and healthy well into our 80s or in terrible shape and dying young. Mind you, these are not "definites" because nothing can give you a guarantee, but they are ways we can improve our odds in living the long and healthy life that we want. From Medical Xpress:

A healthy lifestyle adds years to life

Live longer thanks to fruit, an active lifestyle, limited alcohol and no cigarettes. This is the conclusion of a study by public health physicians at the University of Zurich who documented for the first time the impact of behavioural factors on life expectancy in numbers. 

...Brian Martin and his colleagues from the Institute of Social and Preventive Medicine (ISPM) at the University of Zurich have examined the effects of these four factors – both individual and combined – on life expectancy. An individual who smokes, drinks a lot, is physically inactive and has an unhealthy diet has 2.5 fold higher mortality risk in epidemiological terms than an individual who looks after his health. Or to put it positively: "A healthy lifestyle can help you stay ten years' younger", comments the lead author Eva Martin-Diener.

"The effect of each individual factor on life expectancy is relatively high", states Eva Martin-Diener. But smoking seems to be the most harmful. Compared with a group of non-smokers, smokers have a 57 percent higher risk of dying prematurely. The impact of an unhealthy diet, not enough sport and alcohol abuse results in an elevated mortality risk of around 15 percent for each factor.

According to Martin an unhealthy lifestyle has above all a long-lasting impact. Whereas high wine consumption, cigarettes, an unhealthy diet and physical inactivity scarcely had any effect on mortality amongst the 45 to 55-year-olds, it does have a visible effect on 65 to 75-year-olds. The probability of a 75-year-old man with none of the four risk factors surviving the next ten years is 67 percent, exactly the same as the risk for a smoker who is ten years younger, doesn't exercise, eats unhealthily and drinks a lot.

From Medical Xpress:

Picking up healthy habits in your 30s and 40s can slash heart disease risk

The heart is more forgiving than you may think—especially to adults who try to take charge of their health, a new Northwestern Medicine study has found. When adults in their 30s and 40s decide to drop unhealthy habits that are harmful to their heart and embrace healthy lifestyle changes, they can control and potentially even reverse the natural progression of , scientists found. On the flip side, scientists also found that if people drop  or pick up more bad habits as they age, there is measurable, detrimental impact on their coronary arteries.

For this paper, scientists examined healthy lifestyle behaviors and coronary artery calcification and thickening among the more than 5,000 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study who were assessed at baseline (when participants were ages 18 to 30) and 20 years later.The healthy  assessed were: not being overweight/obese, being a nonsmoker and physically active and having low alcohol intake and a healthy diet. 

By young adulthood (at the beginning of the study), less than 10 percent of the CARDIA participants reported all five healthy lifestyle behaviors. At the 20-year mark, about 25 percent of the study participants had added at least one healthy lifestyle behavior. Each increase in healthy lifestyle factors was associated with reduced odds of detectable  and lower intima-media thickness—two major markers of cardiovascular disease that can predict future cardiovascular events. Adulthood is not too late for healthy behavior changes to help the heart."

"That loss of healthy habits had a measurable negative impact on their coronary arteries," Spring said. "Each decrease in healthy lifestyle factors led to greater odds of detectable  calcification and higher intima-media thickness.

Spring said the healthy changes people in the study made are attainable and sustainable. She offers some tips for those who want to embrace a  at any age:Keep a healthy body weight; Don't smoke; Engage in at least 30 minutes of moderate to vigorous activity five times a week; No more than one alcoholic drink a day for women, no more than two for men; Eat a healthy diet, high in fiber, low in sodium with lots of fruit and vegetables.

From Science Daily:

Adults who lose weight at any age could enjoy improved cardiovascular health

Weight loss at any age in adulthood is worthwhile because it could yield long-term heart and vascular benefits, suggests new research. For the first time, the findings indicate that adults who drop a BMI category -- from obese to overweight, or from overweight to normal -- at any time during adult life, even if they regain weight, can reduce these cardiovascular manifestations. The findings are from a study examining the impact of lifelong patterns of weight change on cardiovascular risk factors in a group of British men and women followed since birth in March 1946.